Speed regulator



oct. 18, 1927.

H. E. WARREN SPEED REGULATOR Filed Jan. 4. 1924 @ze /2//3 #R l *H s /4- v Vo v Y ruvev'nbor:

Henrg Ewa'rre;

His AbnoreH-g Patented oa. 1s, 1927.l y, UNITED STATES 1,646,269 4PA'IENT OFFICE.

HENRY AE. WARREN, F ASHLAND, MASSACHUSETTS, ASSIGNOR TO WARREN CLOCK (LOMRALBTY.A OF ASHLAND, MASSACHUSETTS, A CORPORATION 0F MAINE.

SPEED REGULATOR.

l Application and January `4, 1924.. serial No. 634,459.

My. invention relates to the speed control of dynamo electric machines, and especially to i the control of machines whlch are required to be operated at constant speed or at speeds which change but slightly from a constant value.

In the operation of electric machines it is frequently desirable that the speed be maintained within narrow limits.` Thus, for example, in the case of rotary converters or generators utilized to operate clocks or to supply currentfor 'use vin wireless trans-I mission systems it is of the utmost importance that considerable variations in speed be prevented. In accordance with my invention meansresonant to .a certain.definite frequency are arranged to control the excitation and consequently the speed ofthe machine. In one embodiment of vmy invention this is accomplished'by resistor means associated with the eld Acircuit of the machine and controlled in response to the value of current in a tuned circuit upon which is impressed a voltage having a fre-V quency which is proportional to the speed of the machine.

An object of my invention is to provide an improved speed regulating means operable in response to variation in the fre-y quency of a voltage generated by the machine tov control the machine speed. A further object is to provide an improved means by which the heating effect of one current of electricity may be utilized to control the value of another current of electricity. v

My invention will be better understood on reference to the following description when considered in connection with the accompanying diagrammatic drawings and its scope will be pointed out by the appended claims.

Referring now to the drawing, Fig. 1 shows a speed control system in which my invention has been embodied; Fig. 2 shows my invention as-applied in a modified form; and Fig. 3 shows a further modification.

Fig. lshows a rotary converter 1 toperatively associated with the direct current line 2 through switch 3 and brushes 4. Connected to the slip rings 5 and brushes 6 of the converter 1 is the primary winding 7 of a transformer 8, the secondary winding 9 of which is arranged to impress an alternating voltage. onv a tuned circuit comprising' a current controlling device 10, a condenser 11.

for excluding direct current from the tuned circuit, and a lter 12 which consists of reactor 13, fixed condenser 14 and variable condenser 15 connected in parallel. A load device, illustrated as a clock 16, is shown as arranged to be supplied with current from the secondary winding 9 of the transformer 8. The shunt eld winding 17 of the machine l is connected to the line 2 through a resistor 18 and temperature controlled' in a Wheatstone bridge circuit so that there is no tendency for direct current to ass into the resonant circuit because ofthe act that points 23 and 24 are at the same potential. Points 25 and 26 are likewise points of equal potential and for this reason there is no possibility of alternating current getting into the field circuit of the machine. Like the lamp l0 in Fig. l, lam s 19, 20, 21 and 22 are common to the fiel circuit and the tuned circuit. v

Fig. 3 is a fragmentary view showin a modification suitable for use in connection with large machines. This modification comprises a solenoid having a coil 27 which may be connected to the resonant circuit shown by Figures l and 2 and which. is arranged to operate a lever 28 pivoted at the point 31 through which contacts 29 and 30 are closed and opened to periodically short-circuit a part or all of the field resistor 18 for controlling the effective resistance of the field circuit and consequently the excitation of the machine 1.

Assuming the switch 3 to be in closed position and the machine 1 to -be operated at rool a frequency below that for which the resonant circuit is tuned, alternating current Will be supplied to the metal 'filament of the lamp 10, the resistance of this filament will be increased due to the heating effect of the alternating current, and the direct current supplied from the line 2 to -the ield winding 17 through the filament will be of comparatively low value. The` torque of the machine 1 will therefore be low and it will y'increase its speed until theresonance freuency of the tuned circuit is reached when t e filter 12 operates in well known manner to exclude alternating current from the lamp circuit. When this occurs the reslstance of the lamp lament immediately decreases thereby 'permitting an increase in the excitation and torque of the machine 1 whichslows-down slightly and in doing so decreases the frequencyof the voltageY impressed'on the tuned circuit.- If perfect resonance were reached, the alternating current -for heating. the lam `filament would become practical] negligi le. This would of course tend to ring the speed of the machine far below thatv corresponding to resonance of the wave filter 12. Obviousl a condition of equilibrium will be reache lunder which the filter'12 will ermit sutlicient current to pass through t elamp lament or other control device to maintain the shunt field at such a value as to give almost,but not quite, the speed corresponding with the free vibration of the filter. It is thus possible to regulate the speed of a machine having a shunt field to a high degree of accuracy because by proper choice ofthe wave filter and control lamp or other control devvice almost any desired degree of sensitiveness to extremely small fluctuations in speed ma be obtained.

t is ofcourse obvious that the controlling current need not pass through'the lamp filament or other control.. means since the l same effect may be produced by otherwise utilizing it to produce heat b which the effective resistance of the field clrcuit is controlled.l I .accordinglydo not wish to be vrestricted to the particular forms of 'constructlon disclosed herein by way of examforth my inple for the purpose of setting t e patent statvention in accordance with utes. The terms of the appended claims. -are,'.tl lerefo re, not restricted to the recisev structure disclosed, but are inten ed to cover all changes and modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is v:-

1. A speediregulator for re ulating the l speed of a dynamo electric mac ine rovided with a field windingarranged to esup- 1 plied with current for exciting said machine and with an armature winding having alternating current terminals, n comprising means including a' tuned circuit'operatively associated with said alternating current terminals, and means conductively associated with said eld winding and said tuned cir-l 'speed of a dynamo electric mac cuit for controlling lthe excitation of said machine in response to its speed.

2. A speed regulator for relllating the e provided with a field winding arranged to be supplied withv current for excitin said machine and with an armature winding having alternating current terminals, comprising means for controlling the current supplied to said field winding, and a tuned circuit conductively associated with said control means and said alternating current terminals for controlling the lexcitation of said machine, said field current. control means beingarranged to preclude the supply of current to said ield winding and to said tuned circuit from a common. source.

. 3. A speed regulator for regulating the speed of a dynamo electric machine provided with a field winding arranged to be supplied with` current for exciting said machine and with an armature Winding having alternating current terminals, comprising resistor means for controlling the current supplied to said field winding, and a tuned circuit operaltively associated with said. alternating curarranged in a Wheatstone bridge circuit for controlling the current supplied to said field winding, and a tuned circuit. operatively associated with-'said altenating current terminals for controlling' the tem era- .ture of said" resistor means 1n accor ance with the frequency of the voltage impressed on said terminals.V

5. A speed regulator for regulating the eed of a dynamo electric machine provided with a field winding arranged to be supplied with direct current for exciting said machine and with a generating winding having alternating current terminals comprising resistor means for controlling the current supplied to said field winding, and a1 tuned circuit operatively associated with said alternating current terminals 'for controlling the temperature of said resistor means, said resistor means being arranged to exclude direct current from said tuned circuit.

6. A speed regulator for regulating the speed of a dynamo electric machine provided with a field winding arranged to-be supplied with excitationfrom a source of direct current andwith a generating winding having alternating current terminals, comprising resistor-.means arranged in a Wheatstone bridge circuit havin one set of terminals connected to said vdirect current source in series with said field "winding for controlling the current .supplied to said eld winding from saidsource, anda tuned circuit vcon- 1,646,269 l l a nected to said alternating current Yterminals with the frequency of current delivered by infseries with another set of the terminals V4said machine.

., of said Wheatstone bridge circuit for con- 8. The method of regulating the excitatrolling the temperature of said resistor tion of a dynamovelectric machine provided I means in accordance with the frequency of with a field circuit comprising resistor -means the voltage generated by said machine. and an armature winding associated with a 7. The method of regulating the excitatuned circuit connected to said 4resistor 20 tion of a dynamo electric machine provided means, which comprises controlling said rewith a field circuit comprising resistor means sistor means in accordance with the fre- 10 and an armature winding associated with a quency of current delivered by said machine. Atunedl circuit connected to said resistor I witness whereof, I have hereunto set means, which comprises controlling the temmy hand this 27th day of December, 1923. v perature of said resistor means in accordance 4 HENRY E..WARREN. 

